1. Field of the Invention
The present invention relates to a needle machining apparatus which presents a stock needle to a device for boring a hole in the needle for subsequently securing a suture thereto. More particularly, the present invention relates to a high speed needle feeding apparatus for continuously feeding needle blanks for subsequent laser drilling.
2. Description of the Related Art
Surgical sutures are generally manufactured by first longitudinally drilling a hole through the end face of a blank stock needle, bending the needle to a desired curvature, inserting an appropriate suture into the hole and crimping or otherwise securing the suture material to the needle. Generally, there are numerous ways to drill or cut the hole in the end face. For example, the hole may be made by drill machining, electric discharge machining, laser beam machining, electron beam machining and the like. With the advent of microsurgical procedures, surgical sutures have become increasingly smaller in size, thus making it more complex and costly to manufacture the surgical needles. In particular, one aspect of surgical suture manufacturing which has become complex is drilling the hole in the needle.
A common procedure for making a hole in a surgical needle utilizes laser or electron beam machining. In order to utilize these methods in a production environment, techniques have been developed to continuously present a blank needle before the beam for cutting. One such technique includes presenting the blank needle from a rotary spool which is sequentially rotated to present an end face in line with the focal plane of the laser or electron beam. However, one drawback to this technique is that the rotating spool must stop before the beam is impinged on the needle. In order to operate properly the spool must come to a rest at precisely the same position aligned with the focus point of the beam. If the needle in the rotating spool is not aligned with the focus point of the beam, even by an infinitesimal amount, the centrality of the hole would be off center, thereby reducing the accuracy of the production process and ultimately resulting in increased defective quantities of needles. Currently, rotary spool systems are unable to obtain the precise positioning required for laser or electron beam machining. This lack of precision is magnified as the speed in which the blank needle is presented increases. As a result, the reliability and accuracy of rotary spool feeding systems is unacceptable in a high volume production environment.
Another technique utilized has been to bundle blank needles into a container, digitize an image of the needle faces in the bundle and move the laser or electron beam to focus sequentially on each needle before firing the beam. These types of beam machining devices also have drawbacks, such as the need to optically determine where each needle is and then move the beam to coincide with the longitudinal axis at the center of the needle. Such systems are complex and require additional steps in order to determine the precise position of each needle. As a result, the speed of producing sufficient quantities to satisfy production needs is decreased.
Therefore, a need exists for a precise needle blank feeding system which can be reliably operated at high speeds and which does not require movement of the laser or electron beam.